Sol–gel encapsulated transition metal quaternary ammonium ion pairs as highly efficient recyclable catalysts

1993 ◽  
pp. 583-584 ◽  
Author(s):  
Ayelet Rosenfeld ◽  
David Avnir ◽  
Jochanan Blum
Keyword(s):  
Transition Metal ◽  
Quaternary Ammonium ◽  
Sol Gel ◽  
Ion Pairs ◽  
Ammonium Ion ◽  
Highly Efficient ◽  
Recyclable Catalysts

Comparison between homogeneous and sol-gel-encapsulated rhodium-quaternary ammonium ion pair catalysts

1996 ◽  
Vol 107 (1-3) ◽  
pp. 217-223 ◽  
Author(s):  
Jochanan Blum ◽  
Ayelet Rosenfeld ◽  
Nava Polak ◽  
Osnat Israelson ◽  
Herbert Schumann ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Sol Gel ◽  
Ion Pair ◽  
Ammonium Ion

Disproportionation of Dihydroarenes by Sol–Gel Entrapped RhCl3-Quaternary Ammonium Ion Pair Catalysts

1996 ◽  
Vol 164 (2) ◽  
pp. 363-368 ◽  
Author(s):  
Ayelet Rosenfeld ◽  
Jochanan Blum ◽  
David Avnir
Keyword(s):  
Quaternary Ammonium ◽  
Sol Gel ◽  
Ion Pair ◽  
Ammonium Ion

Heteroditopic Transition Metal Dithiocarbamate Receptors for Binding Cation-Anion Ion Pairs

2002 ◽  
Vol 2 (1-3) ◽  
pp. 89-92 ◽  
Author(s):  
Neil G Berry ◽  
Thomas W Shimell ◽  
Paul D Beer
Keyword(s):  
Transition Metal ◽  
Ion Pairs

scholarly journals A gold-catalyzed alkyne-diol cycloisomerization for the synthesis of oxygenated 5,5-spiroketals

2011 ◽  
Vol 7 ◽  
pp. 570-577 ◽  
Author(s):  
Sami F Tlais ◽  
Gregory B Dudley
Keyword(s):  
Transition Metal ◽  
Lewis Acids ◽  
Gold Catalysis ◽  
Late Transition Metal ◽  
Efficient Synthesis ◽  
Highly Efficient ◽  
Late Transition

A highly efficient synthesis of oxygenated 5,5-spiroketals was performed towards the synthesis of the cephalosporolides. Gold(I) chloride in methanol induced the cycloisomerization of a protected alkyne triol with concomitant deprotection to give a strategically hydroxylated 5,5-spiroketal, despite the potential for regiochemical complications and elimination to furan. Other late transition metal Lewis acids were less effective. The use of methanol as solvent helped suppress the formation of the undesired furan by-product. This study provides yet another example of the advantages of gold catalysis in the activation of alkyne π-systems.

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